#include <iostream>
using std::string;

class Sales_item{
	public:
		double avg_price() const;
		bool same_isbn(const Sales_item &rhs) const
		{
			return isbn == rhs.isbn;
		}
		void set_sales();
		void print_sales();
		Sales_item() : units_sold(0), revenue(0.0){}
	private:
		string isbn;
		unsigned int units_sold;
		double revenue;
};
